Bottom Line:
Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers.Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties.Contact angles as high as 160° are obtained with 30% polymer dopant.

ABSTRACTThe synthesis of a family of new poly(lactic acid-co-glycerol monostearate) (PLA-PGC18) copolymers and their use as biodegradable polymer dopants is reported to enhance the hydrophobicity of poly(lactic acid-co-glycolic acid) (PLGA) nonwoven meshes. Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers. Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties. Contact angles as high as 160° are obtained with 30% polymer dopant. Lastly, these meshes are nontoxic, as determined by an NIH/3T3 cell biocompatibility assay, and displayed a minimal foreign body response when implanted in mice. In summary, a general method for constructing biodegradable fibrous meshes with tunable hydrophobicity is described for use in tissue engineering and drug delivery applications.

Mentions:
The in vivo biocompatibility and foreign bodyreaction to electrospun meshes were assessed 4 weeks after subcutaneousimplantation in mice (Figures 4 and 5). A separate group of meshes was melted to eliminatesurface roughness and therefore act as a nonsuperhydrophobic controlwith identical polymer composition. In general, meshes experienceda greater degree of tissue ingrowth (arrows) by macrophages and fibroblastscompared to films, as may be expected given the greater degree ofporosity. Nonetheless, all meshes and films (labeled with arrowheads)were well-tolerated in mice and showed minimal signs of fibrous encapsulation(arrows). Fibrous encapsulation is characteristic of a foreign bodyresponse to an implanted device.48 A smallnumber of macrophages are indeed present at 4 weeks after implantationas part of a mild inflammatory reaction. This is to be expected aspart of the normal host response to an implanted material that persiststo this time point. The foreign body response to the superhydrophobicmeshes (Figure 4) was similar to that of implantedPLGA meshes and smooth (i.e., nonsuperhydrophobic) PLGA films dopedwith 30% PLA–PGC18 (60:40) (Figure 5). Furthermore, these results are similar to electrospun PCLmeshes implanted in rats performed by Cao et al.49 Their study also examined the effect of fiber orientation(i.e., random or aligned) on fibrous capsule thickness and foreignbody giant cell count, and they concluded that the fibrous architecturewas capable of minimizing the foreign body response compared to thatof smooth films and that thinner fibrous capsules were observed forthe aligned fiber meshes compared to that of the meshes with randomlyoriented fibers.

Mentions:
The in vivo biocompatibility and foreign bodyreaction to electrospun meshes were assessed 4 weeks after subcutaneousimplantation in mice (Figures 4 and 5). A separate group of meshes was melted to eliminatesurface roughness and therefore act as a nonsuperhydrophobic controlwith identical polymer composition. In general, meshes experienceda greater degree of tissue ingrowth (arrows) by macrophages and fibroblastscompared to films, as may be expected given the greater degree ofporosity. Nonetheless, all meshes and films (labeled with arrowheads)were well-tolerated in mice and showed minimal signs of fibrous encapsulation(arrows). Fibrous encapsulation is characteristic of a foreign bodyresponse to an implanted device.48 A smallnumber of macrophages are indeed present at 4 weeks after implantationas part of a mild inflammatory reaction. This is to be expected aspart of the normal host response to an implanted material that persiststo this time point. The foreign body response to the superhydrophobicmeshes (Figure 4) was similar to that of implantedPLGA meshes and smooth (i.e., nonsuperhydrophobic) PLGA films dopedwith 30% PLA–PGC18 (60:40) (Figure 5). Furthermore, these results are similar to electrospun PCLmeshes implanted in rats performed by Cao et al.49 Their study also examined the effect of fiber orientation(i.e., random or aligned) on fibrous capsule thickness and foreignbody giant cell count, and they concluded that the fibrous architecturewas capable of minimizing the foreign body response compared to thatof smooth films and that thinner fibrous capsules were observed forthe aligned fiber meshes compared to that of the meshes with randomlyoriented fibers.

Bottom Line:
Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers.Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties.Contact angles as high as 160° are obtained with 30% polymer dopant.

ABSTRACTThe synthesis of a family of new poly(lactic acid-co-glycerol monostearate) (PLA-PGC18) copolymers and their use as biodegradable polymer dopants is reported to enhance the hydrophobicity of poly(lactic acid-co-glycolic acid) (PLGA) nonwoven meshes. Solutions of PLGA are doped with PLA-PGC18 and electrospun to form meshes with micrometer-sized fibers. Fiber diameter, percent doping, and copolymer composition influence the nonwetting nature of the meshes and alter their mechanical (tensile) properties. Contact angles as high as 160° are obtained with 30% polymer dopant. Lastly, these meshes are nontoxic, as determined by an NIH/3T3 cell biocompatibility assay, and displayed a minimal foreign body response when implanted in mice. In summary, a general method for constructing biodegradable fibrous meshes with tunable hydrophobicity is described for use in tissue engineering and drug delivery applications.